使用datareader将多行数据读入同一文本框。 [英] Reading multi-rows of data into the same textbox with datareader.

问题描述

我无法弄清楚我做错了什么。我试图将多行数据读入同一文本框。我正在使用Datareader。让我解释一下我想要做什么。



我正在申请中创建客户备注/评论部分。我想存储有关客户服务对话的注释/评论。我正在用日期&存储它们评论被添加的时间。它存储在Access数据库中。我想检索数据并将其显示在winform上。我选择了一个多行文本框。我可以将数据显示在文本框中，但它只显示具有多个记录的客户的最后一条记录。



我不确定是否可能，有没有更好的方式或我错过了什么。



我尝试过：



CustomerNotes表：



CusNumber日期/时间评论

1350 3/29/2019 8:52:42 AM客户想要退款。

1376 8/23/2018 10:52:42 PM他们对产品不满意。

1350 4/4/2019 2:43:11 PM我们发出退款。





Textbox结果我想要：



3/29/2019 8:52:42 AM

客户想要退款。



4/4/2019 2:43:11 PM

我们发出退款。



我的代码：

 尝试 
  Dim  command = 新 OleDb.OleDbCommand 
 致电 connection（）
  Dim  drCustomerNotes  As  OleDbDataReader =  Nothing  
 
 使用 cm 
 .Connection = con 
 .CommandText =   SELECT * FROM tblCusNotes WHERE fldCusNote sAcctNo = @CusAcctNo 
 尝试 
 .Parameters.Clear（）
 .Parameters.Add（  @ CusAcctNo，OleDbType。 Integer ）。值= tbCusAcctNo.Text 
  Catch  ex  As 异常
 MsgBox（ex.Message， MsgBoxStyle.Critical）
 结束 尝试 
 drCustomerNotes = .ExecuteReader 
 结束 使用 
   drCustomerNotes .Read（）
 
 CusNotesTemp = drCustomerNotes（  fldCusNotesDateEntered）。ToString 
 CusNotesTemp = CusNotesTemp + vbCrLf + drCustomerNotes（  fldCusNotesText）。ToString + vbCrLf 
 tbCusNotes。 Text = CusNotesTemp 
 CusNotesfound =  True  
  End   while  
 
 ' 如果CusNotesfound = True则MsgBox（Cus Notes Info Found。，MsgBoxStyle.Information） 
 如果 CusNotesfound =  False  然后 MsgBox（  Cus Notes Info Not Found。，MsgBoxStyle.Information）
 drCustomerNotes.Close（）

我用上面的代码得到的文本框结果：



4 / 4/2019 2:43:11 PM

我们发出了退款。

解决方案

也许下面的内容？将文本框移到循环外部，将循环内的字符串连接起来，然后将其绑定到文本框

 CusNotesTemp =   
   drCustomerNotes.Read（）
 
 '  CusNotesTemp = drCustomerNotes（fldCusNotesDateEntered）。ToString  
 CusNotesTemp = CusNotesTemp + drCustomerNotes（  fldCusNotesDateEntered）。ToString + vbCrLf + drCustomerNotes （  fldCusNotesText）。ToString + vbCrLf 
 '  tbCusNotes.Text = CusNotesTemp  
 CusNotesfound =  True  
 结束  while  
 
 tbCusNotes.Text = CusNotesTemp 

您也可以尝试连接StringBuilder类的字符串。

在.NET中使用StringBuilder类| Microsoft Docs [ ^

I can't figure out what I am doing wrong. I am trying to read multiple rows of data into the same textbox. I am using a Datareader. let me explain what I am trying to do.

I am creating a customer notes/comments section in my application. I want to store notes/comments about customer service conversation. I am storing them with the date & time the comment was added. This is stored in a Access database. I want to retrieve the data and display it on a winform. I have choosen a multi-line textbox. I can get the data to display in the textbox but it only displays the last record of a customer that has multiple records.

I'm not sure if it is possible, is there a better way or what am I missing.

What I have tried:

CustomerNotes table:

CusNumber Date/Time Comment
1350 3/29/2019 8:52:42 AM Customer is wanting a refund.
1376 8/23/2018 10:52:42 PM They were not happy with the product.
1350 4/4/2019 2:43:11 PM We issued a refund.


Textbox result that I want:

3/29/2019 8:52:42 AM
Customer is wanting a refund.

4/4/2019 2:43:11 PM
We issued a refund.

My code:

Try
            Dim command = New OleDb.OleDbCommand
            Call connection()
            Dim drCustomerNotes As OleDbDataReader = Nothing

            With cm
                .Connection = con
                .CommandText = "SELECT * FROM tblCusNotes WHERE fldCusNotesAcctNo = @CusAcctNo"
                Try
                    .Parameters.Clear()
                    .Parameters.Add("@CusAcctNo", OleDbType.Integer).Value = tbCusAcctNo.Text
                Catch ex As Exception
                    MsgBox(ex.Message, MsgBoxStyle.Critical)
                End Try
                drCustomerNotes = .ExecuteReader
            End With
            While drCustomerNotes.Read()

                CusNotesTemp = drCustomerNotes("fldCusNotesDateEntered").ToString
                    CusNotesTemp = CusNotesTemp + vbCrLf + drCustomerNotes("fldCusNotesText").ToString + vbCrLf
                tbCusNotes.Text = CusNotesTemp
                CusNotesfound = True
                End While

            'If CusNotesfound = True Then MsgBox("Cus Notes Info Found.", MsgBoxStyle.Information)
            If CusNotesfound = False Then MsgBox("Cus Notes Info Not Found.", MsgBoxStyle.Information)
            drCustomerNotes.Close()

Textbox result that I get with the above code:

4/4/2019 2:43:11 PM
We issued a refund.

解决方案

Maybe something like below? Move the textbox outside the loop, concatenating the string inside the loop, then bind it to the textbox

CusNotesTemp = ""
While drCustomerNotes.Read()

       ' CusNotesTemp = drCustomerNotes("fldCusNotesDateEntered").ToString
            CusNotesTemp = CusNotesTemp + drCustomerNotes("fldCusNotesDateEntered").ToString + vbCrLf + drCustomerNotes("fldCusNotesText").ToString + vbCrLf
       ' tbCusNotes.Text = CusNotesTemp
        CusNotesfound = True
        End While

tbCusNotes.Text = CusNotesTemp

You can also try concatenate the string with StringBuilder class.
Using the StringBuilder Class in .NET | Microsoft Docs[^]

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